The Talmud says that through the Hallel we have the ability to break the roof. A roof is something above us is analogues to ego that causes us to feel greater then we really are. Through the recitation of the Hallel, by reciting the praise of the almighty, we realize how small and insignificant we really are, thus breaking our sense of ego.
(מחשבות חרוץ מר’ צדוק הכהן מלובלין עמ’ סז)